
import java.util.Scanner;

public class RadiusCalc {

    public static void main(String[] args) {

        System.out.println("Enter the area: ");

        Scanner input = new Scanner(System.in);

        double area = input.nextDouble();

        if (area > 0) {
            double radius = Math.sqrt(area / Math.PI);
            System.out.println("The radius is " + radius);
        } else {
            System.out.println("Error: invalid area");
        }
    }
}
